This invention relates to a door lock for an elevator car. More particularly, it relates to a door lock for an elevator car which is easier and less expensive to install than a conventional door lock.
The doors of an elevator car are typically equipped with a door lock which prevents the doors from being opened unless the location of the elevator car within the elevator shaft is such that it is safe for the doors to open. As it is necessary that the lock continue to operate even when electrical power to the elevator is cut off, such as during a power failure, it must be possible for the door lock to be locked and unlocked mechanically. For example, Japanese Examined Published Patent Application No. 59-17031 discloses an elevator car door lock with a mechanical latch which is latched or unlatched in accordance with whether there is contact between a pivot arm, which is mounted on the elevator car, and a cam, which is secured to the inside of the elevator shaft. The cam is a member which projects from the side of the elevator shaft and extends vertically for the entire length of the elevator shaft except for those locations where it is safe for the elevator car doors to open. The latch operates such that the elevator car doors are locked when the pivot arm contacts the cam, and the doors are unlocked when there is no contact therebetween.
With this structure, the cam which is used to operate the latch is extremely long and cumbersome, and therefore it is time-consuming and expensive to install and adjust the cam.